Opioid CYP2D6 Genotyping

CPT: 81226
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Synonyms

  • Codeine
  • Cytochrome P450

Expected Turnaround Time

7 - 10 days



Related Documents

For more information, please view the literature below.

Pharmacogenetic Testing for Pain Specialists


Specimen Requirements


Specimen

Whole blood or LabCorp buccal swab kit (buccal swab collection kit contains instructions for the use of a buccal swab)


Volume

7 mL whole blood or LabCorp buccal swab kit


Minimum Volume

3 mL whole blood or two buccal swabs


Container

Lavender-top (EDTA) tube, yellow-top (ACD) tube, or LabCorp buccal swab kit (PeopleSoft N° 3177).


Storage Instructions

Maintain specimen at room temperature or refrigerate at 4°C.


Causes for Rejection

Frozen or hemolyzed specimen; quantity not sufficient for analysis; improper container; wet buccal swab; one buccal swab


Test Details


Use

This testing can assist with customizing drug therapy by providing metabolic activity information that may explain patient drug responses relevant to CYP2D6 genetic variability. The cytochrome P450 (CYP450) enzymes metabolize many drugs. Individual genetic differences of cytochrome P450 activity can result in the total absence of metabolism to ultrafast metabolism of certain drugs.


Limitations

This assay does not detect other variants in the CYP2D6 gene that may affect metabolic activity. The metabolism of drugs may also be influenced by race, ethnicity, diet, and other medications. All factors should be considered prior to initiating new therapy. This test result does not rule out the possibility of variant alleles in other drug metabolism pathways.


Methodology

DNA analysis of the Cytochrome P450 2D6 gene (OMIM 124030) is performed using primer extension chemistry. Multiplex PCR amplifies DNA fragments containing the variants below. Primer extension then generates a biotin-labeled product to permit flow-sorted detection of both normal and variant sequences. Molecular-based testing is highly accurate, but as in any laboratory test, rare diagnostic errors may occur.

Alleles detected:

*1, *2, *3, *4, *5, *6, *7, *8, *9, *10, *11, *15, *17, *29, *35, *41, and gene duplications.

Variant *5 is a gene deletion. Copy number of duplicated alleles is not determined. Duplications are often functional (whole gene) but may be nonfunctional (partial gene). It is not always possible to determine which allele is duplicated.

*1 represents detection of the normal sequence for the variants tested.


Additional Information

CYP2D6 is involved in the metabolism of opioid analgesics such as codeine, hydrocodone, dihydrocodeine, oxycodone, and tramadol.

Codeine is O-demethylated to its more active form, morphine, by CYP2D6-encoded enzymes. Variation in the CYP2D6 gene can result in ultrarapid, normal (extensive), normal to intermediate, intermediate, and poor metabolizer phenotypes. Ultrarapid metabolizers may experience exaggerated or even potentially dangerous opioid side effects after codeine administration, including euphoria, dizziness, epigastric pain, and/or visual disturbance. For poor metabolizers, a reduced analgesic effect may be observed due to insufficient biotransformation of codeine to its more active form, morphine.


References

Crews KR, Gaedigk A, Dunnenberger HM, et al. Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for cytochrome P450 2D6 genotype and codeine therapy:2014 update. Clin Pharmacol Ther. 2014 Apr;95(4):376-382.24458010
Hicks JK, Bishop JR, Sangkuhl K, et al. Clinical pharmacogenetics implementation consortium (CPIC) guideline for CYP2D6 and CYP2C19 genotypes and dosing of selective serotonin reuptake inhibitors. Clin Pharmacol Ther. 2015 Aug;98(2):127-134.25974703
Hicks JK, et al. Clinical pharmacogenetics implementation consortium (CPIC) guideline for CYP2D6 and CYP2C19 genotypes and dosing of tricyclic antidepressants. Clin Pharmacol Ther. 2013 May;93(5):402-408.
LabCorp Pharmacogenetic Testing flyer (L14582). Available upon request.16819548
Trescot AM, Faynboym S. A review of the role of genetic testing in pain medicine. Pain Physician. 2014 Sep-Oct;17(5):425-445.25247900
Vuilleumier PH, Stamer UM, Landau R. Pharmacogenetic considerations in opioid analgesia. Pharmgenomics Pers Med. 2012;5:73-87.23226064

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
511380 Opioid CYP2D6 Genotyping 504202 2D6 Genotype: 40425-1
511380 Opioid CYP2D6 Genotyping 504203 2D6 Metabolic Activity: 79715-9
511380 Opioid CYP2D6 Genotyping 504631 Director Review: 69426-5
511380 Opioid CYP2D6 Genotyping 504388 Interpretation: 72880-8
511380 Opioid CYP2D6 Genotyping 504389 CYP2D6 Information: 49549-9
511380 Opioid CYP2D6 Genotyping 000000 MGRM Informed Consent Review N/A

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